Prism-glass reflector for artificial lights.



0. A. MXGATT. PRISM GLASS REFLECTOR FOR ARTIFICIAL LIGHTS. APPLIOATIOH IILE D HARM, 1904.

988,488. Patented Apr.4,1911.

rally on the glass reflectors.

ter thereof, either llli lli cars A. sweater, or new irons, N. r.

Persia-erase nnmnoron FOIt anrrrrcmn LIGHTS.

assess.

Specification of Letters Patent.

Patented Apr. it, ltiliil Application filed March 24, 1904. Serial 1%. 199,721.

Y '0 all whom it may concern: 1

v Be it known that l. OTIS it. Maworrrr, a

citizen of the United States residing at New York, in the county of New York and State of New York, have invented certain new and itiseful Improvements in Prism Glass lieflectors for Artificial Lights. of which the following is a specification.

This invention relates to prism glass reflectors, for artificial lights.

mum efficiency, assuming that the prisms are of the character illustratedin detail in Figure and in elevation in the upper part of Figs. 1 and 3 of my Patent No. 736,535, oil-tug. 18. 1903; In iny Design Patents mnnl'iered 35,7!5, 35,?56, and 35,757. of Feb. 18; 1902, i show reflectors With external prisms of the some general Cliltll'fltllfil, but arranged 'spi This spi 'al ar rangenicnt of prisms is by some considered more ornamental than the radial arrangement of prisms in the patents first above referred to, hut is less elficient for the purpose of reflect-ion of light in a downward direction, for reasons I Will explain hereinafter. In all the constructions of prism glass rcilectors above referred to, therefiectors are oi. greater circumference at the base or lower part than at the apex or upper part, being hollow frustinns of cones, spheres or spheroids, or combinations of 'suchgeometrical forms. in most of the prismatic reflectors heretofore constructed by me each; prism Was constructed to extend from a point at or near the center or smallest part of the reflector to the base or part of greatest diamein lunar or iri spiral form.

In either case. as a-prism approachedihe periphery of the reflector it necessarily increased in. helght and breadth, in order to retain its proper angular and reflective re lation to the beams or lines of lightemanating-within the reflector; This increase in hewiilth and height of the prisms is ob VJ i3i01'1al)l{ for two important reasons. The ent re reflector is thereby made much heavier, reasmg the cost and mc-reasing the cost Fig. 6 an end View in tllzigi'fiil'lihln'ti? illnsof 90 degrees in' the direction of of fixtures tohoh'l it. The rctiector is also rendered less efiicient. sincethick glass ahsorhs light in proportion to its thickness. thereby neutralizing its J'CllCUtiYL action to' such extent.

The present invention largely reduces the Weight of prismatic glass reflectors, thereby reducing cost, providing for jifitllfil' ciliciency,'and also atl'ording' large tilij'nflttlllit) for ornamental and decorative charts; in prism glass reflectors for artificial lights. The ribs (fr prismsvary in ninnl'ier in-adiacent series ivithin a. given area. .lt is this characteristic, anion; others. which gives the glassware the qualities set Forth in tho. s -iec-ifieation.

Fig. 1 is .a side elevation of part ol' a prismatic reflector. illustrating the principles of my invention. Fit. 2 is a similar elevation of part. of a modified and tlOCUl'tl-- tive reflector involving like principles. l igg 3 is a diagram illustrating a section ot a. prismatic glass reflector. showing a dark or shaded sui't'ace intended to llliod'mte the area or elciaiion ot a prisni oi the construetion shown in my patent first referred to, and a series of light surfaces intended to illustrate th area or elevation ot a series of prisms 0i. substantially equal or greater reflcctive power am-ordiiiig to the present invention. Fig. l is a perspective diagram oil a prism which l call a double. reflective. prisnninrlicatingr the course oft a. single ray of light. Fig. is a perspective diagram of a spiral]; arranged donhlc reflective prism, sl'io'wing direction oi some light 1? which are not reflected from snch a pri tration of one of a lower series of prisms, showing in shade lines the triangular area of the first prism of the first series. it produced "in symmetrical form.

In prismatic gl: ss reflectors the-most e'i" fective reflecting faces of the prisms are those faces against which the which enter the reflector from Within, strike the outer face off the prism at an angle of 4-5 degrees, as in the line a, Fig. 4.. Such a ray is reflected by the surface 5, in the direction oi. 0, fornnngat & an angle of degrees.

At '0 the light ra} again strikes a surface inolined at an angle of L5 degrees to the line of its movement or clirec'ion. Again or a second time'the ray is reflected at an angle light rays llti . double reflection of some light rays will take place it the prisms are notinciined exactly at angles of 45' degrees, the limit of effective reflection being some seven or eight degrees on either side'of the 45 degree inclination from the line a. In the spirally arranged prisms on the same form of reflector, some of the light rays as a must encounter the reflecting surface as b at an angle greater or less than elf? degrees. A part of the ray passes through in the direction I)", and a' part is reflected 1n the direction (l, While apart is reflected across the prism to the surface c, and passes out in the direction 0. It is obviously impossible to illustrate the direction oi a very large number' of light rays in a diagram. The illustration applies to many of the rays. But from large expert once I am convinced that the most ell'ectivo prismatic glass reflectors are those in which the prisms are arranged with their longer axes on radial lines on the outer face of a rrllertorsurrounding the light. Nevertheless my present invention is equally adaptable to.thc spiralor other arrangement of prisms. with an equal. saving of weigl'it.

In Fig. 1, let A indicate a broken side view of one of my improved reflectors. The reflector shown is of the well 'known conical forlmbut may be arched and may be either opener closed at the top. Prisms B are of the character shown in the patents first referred to, are integral with the body A, and reflect light rays from within in the manner illustrated in Fig. 4: herein. But instead of extending from the neck of the reflector to thc'rim D, as in the patents and designsreferred to. and as represented in the'shaded diagram, Fig. 3, these prisms B terminatealong the line E. A second series of prisms B" begins below the line E. At the lower end of the prisms B there is a reduction in thickness, or downward step from the outer surface of prisms B to the surface of the next lower series of prisms B. As the reflector body A is here larger in diameter, agreater number of prisms of the width of those Bwill be required to surround the re- 'flector. These prisms B, as shown in Fig. 3, will be of considerably less thickness than would be the extension of prisms B in the same direction, and the shaded lines above B in Fig. 3indicate the saving inthe height of prisms, if the desirable reflective angle of 45 degrees is preserved. The prisms B terminate along the line E, and a new. series B begins below that line, and these prisms extend to E Thus at the lower extremity of-any prism there is a reduction in height,

or step down, to the outer surface of the prism in thenext series toward the periphcry of the rclleclor/JX similar arrangement of prisms B is made at the lower side of the horizontal line 15 The diagram, Fig. 5.

illustrates the series, and graphically shows The light is also reflected with less absorplion, from the thinner glass, of the smaller prisms.

Not only is there a great saving in weight by making the prismatic reflectors in short series of smallheight, but great advantage 30' is afforded in the way of decorative efiects.

I' have been able to make'reflectors 0ft. pressed prismatic glass which reflect. as much as per cent.'of thequantity of light received, back into the reflector, and out at the 35 month thereof. This I believe to be about the maximum capacity of pressed prismatic glass, and is rather more than is desirable in most cases as the. reflector is much more at tra'etive in appearance it some light passes through it, and it is also generally desirable that bodies above or. behind the reflector should receive some illumination. By breaking up the prisms into series of smaller prisms, I am able to save'the weight of the large sectional 'area of prisms and save the light absorbed thereby. This enables me to pass a larger quantity of light through the of the outer surface of the glass, to the be-i ginning of the next prism toward the periphery of the reflector. As clearly seen ,in

.Figs. 1 and 2, the lower series of prisms do not necessarily form direct continuations of the prisms of upper series, but the prisms of each lower series begin at a lower. plane, with reference to the body of glass inside the prisms, than the lower terminals of prisms of upper series. That is, there is a step-down'at the lower end of any prism, to the beginning of the next prism toward I the periphery, whether the axes of the prisms follow the same radial lines or not. The terminalv lines or planes 6, 6' may be i at such angles as to permit the passage of more or less light. Thus very brilliant decorative effects may be atained.

As seen clearly at the right hand side in I Fig. 2, the lower ends of prisms of an upper series of prisms project from the body ease-es vai'y'in'length, and are not limited as to their length. a

Fig. 3 illustrateslhc interior of the shade A as smooth. This-is a common form of a plurality of of substantiz are increased in size with construction.- 'As a mattcrof'fact my prismatic construction of the exterior of a. refiector is applicable to reflectors with interiors of other than smooth surface, and except in specific claims, my claims are intended to apply to reflectors having any form ofinterior (:onstruction.

It is obviously impossible to describe and illustrate all thevariox'ls modilhrations which maybe made, so far as arrangement of prisms on the outer surface of reflectors is concerned. The salient; feature of the pres ent invention is that, the prisms have their longer, axes in a. direction generally radial to the body of the reflector, and that the prisms instead of extending from the cell lral portion to the periphery of the reflector,

(as has generally bcen the case lna'eto'forc) are broken up into short series of small prisms extending 1n the same genc'al d1- rection.

The prisms maybe arranged so as to show-almost any desired-ornamental pattern on the outer surface of the reflector. The number of prisms necessary to surround the reflector must of course increase with the diameter of the reflector, unless the prisms the disadvantages hereinhefore stated.

I'm aware that prior to my present application for patent, prismatic glass reflectors had been known in which prisms beginning near the top of the frust-um had extended some distance down the upper outer surface of the frustum, and had been interrupted by ornamental forms or spaces, and then again extended, either o l-the original lines or in lines parallel therewith. lint such a. construction. does not lighten the structure to any considerable extent, as the .lower prisms are practically continuations ot' the upper prisms, and to maintain the proper reflective angle must increase in thickness and height, as if the prisms had not been interrupted. I make my prisms as separate series, and when the prisms of a series reach a moderate height and thickness, that series ceases, and av new series begins, olt' smallersize than the lower ends of the'flrst series, and necessarily greater in I number, if the entire surface of the reflector is covered with prisms. The ribs or plasma of each series are oll'set or out oi line with the ribs or pllSlQS of adjacent, series. In other Words, the glass body is pro ided with \fily parallel ribs, the ribs of the adjacent series being-oilset with respect to one another.

It will also,

series being a eenerally radial direction, th l prisms of the series toward the periphery oflhe reflector increasing in number, over the series. above.

3. A glass reflector for artificial lights" having its exterior provideclaiyqith; i "psorranged in series. the axes of the prisilis extending in a generally radial direction, and prisms of certain of theseries varying in 35 length. 1

l. A shade reflector of glass, having on its outer surface re 1ecting prisms arranged in series, the longer axes of the prisms ex lending ina generally radial direct-ion, certain of the series being composedol prisms of unequal length. and terminating in. lines other than circumferential lines.

:3. A reflector composed of a single piece of glass, having; its out-er surface sul'istantially covered with reflecting prisms ar-- ranged in series, aprisn ofa lower series hav-' in;- a smaller projection from the body of the reflector at its upper end than theprojection of the lower end of a prism in the 1' series. above it. v

(i. A. reflector composed of a single piece of prismatic glass, the outer surface or said reflector being substantially covered with reflecting prisms arranged in series, with the longer axes of the prisms cxtencling in a generally radial direction on the reflector, the prisms of one series being raised in step. like formation above those of the adjacent series. j

7. A reflector composed of glass, the inside V 119 of a single piece of saidreflector being smooth, the outer surface of said reflector beingsubstantially covered with series or integral. prisms having their longer axes ex tending in generally radial directions with reference to; the body of the reflector and calculated to reflect the light, raysfhack into the reflector and out at the open mouth thereof, thoseof one series'being raised in 120 stepwlike formation above those of the. acljacenl; series.

8. A reflector composed of a single piece of glass having a smoothinside and an ex-' ierior snr ace substantially covered with series of light-reflectin prisms, the different superimposed relatively above one another in stcplike formation. I 9." A reflector having-a series of reflecting prisms tlisp'osccl along i' ts outer surface in 18o stepdilto l'ormatibn, a portion of the prisms of a seriesfbeingl'oi' dili'erentlengths from other prisms (if the-{same series. I:

10. A retlet-torhaving a series of reflectin; prisms disposed along its outer surface lll step-lil e formation,-prisms of one series being of dillereiitlengths' from prisms of another series. I

11. retleetm' romposetl of a single piece of lz. s having its miterasurfaee substantially covered with series of reflecting prisms of various lengths,.tht lower ends of the prisms of an upper series projecting from the body of the reflector in step-like Form beyond the upper ends'of prisms of an adjacent lower series. 1 1 2A shade and reflector composed of a single piece of glass and havii'ig a neck for engaging: the walls of the electric bulb or a ehnnney. the inside. of said reflector being smooth, the outer surt'are of said reflector being substantially covered with series of integral prisms ealrulated to reflect the light rays hark into the reflector and out at the open mouth thereol'. tbo.--e of oneseries being raised in step like Formation above those of the adjarent series, substantially as set forth. :v i

12-}. A retlertor having series of reflecting prisms disposed along its outer surface. those of one series being disposed along a curved surface and removed a suitable'distanre from the surface of disposition of the next adjaeent series, substantially a-s set l'orth.- I F "ll. A retlertor or shade having thereon a plurality of substantially parallel ribs arranged in uppe and lower series, the upper ends of the ribs of a lower series bemg-- smaller than the lower endsof the ribs of an upper series. 4 z

15. 'A retleirtor or shade having thereon a plurality of adjarent seriesot"substantially parallel prisms retlertive oflight, the prisms varying in number in adjacent series within a given area.

16. A glass body provided with a plurality of series of substantially parallel ribs retleet-ive and transmissive of light the ribs 1 18. A glass body provided with a plural-' it v of series of substantially parallel ribs retleetive of light, the ribs of adjacent series being otlset with respect to one another.

If rellet-tor or shade having-thereon a plurality of substantially pa 'allel ribs of gradually increasing size arran ed in. upper and lower series, the upper ent s of the ribs ot' a lower series being smaller than the lower ends of the ribsot' an upper series.

30. A glass body provided with a pin ality of substantially parallel reflecting prisms ol gradually increasing size. arranged in upper and lower series, the upper ends of the prisms of a lower series being. smaller than the lower ends ot-lhe prisms of an upper series. r

it. glass body having thereon a pluralit v ot' suhstant ially parallel prisms arranged in upper and lower series, the upper ends of the prisms ot a lower series being smaller and otl'setto the lower ends of the prisms of anupper series. I

ln testimonv whereof I atiix my signature in presence ot two witnesses.

o'risa. MYGATT.

' lVitnesses: v 

